Gaseous discharge register



April 13, 1954 N. B. WALES, JR 2,675,504

GASEOUS DISCHARGE REGISTER Filed March 31, 1950 2 Sheets-Sheet l April 1954 N. B. WALES, JR

GASEOUS DISCHARGE REGISTER 2 Sheets-Sheet 2 Filed March 51 1950 INVENTOR.

Patented Apr. 13, 1954 GASE-OUS DISCHARGE REGISTER Nathaniel B. Wales, Jr., Morristown, N. J., assignor to International Business Machines Corporation, New York, N. Y., a corporation of New York Application March 31, 1950, Serial No. 153,259

6 Claims.

The invention relates to an improvement on the gaseous discharge register disclosed in my co-pending application, serial No. 104,980, filed July 15, 1949.

The basic principle including both the present invention and the above reference comprises the transfer of a glow discharge from one to another of a plurality ofregistering cathodes in response to an input pulse by causing the area of glow to move bodily over the surface of one of these extended cathodes in such a way as to influence the breakdown potential of a particular one of its two adjacent cathodes. In the above disclosure, emphasis was laid on pulses of a polarity such as to increase the area of glow, thereby extending the region of ionization towards the root of the cathode and thus lowering the breakdown potential of the cathode whose tip was adjacent to the energized root. The present invention came about by an investigation of pulses having the opposite polarity to that described above, that is, pulses having a tendency to diminish the area of glow on a given cathode and to extinguish it.

It was observed that tubes built in accordance with the above-mentioned application would count backward when such reversed pulses of extinguishing polarity were applied. A study of this phenomenon indicated that this behavior resulted from the fact that this reversed pulse, on extinguishing the given glow, caused a rise in the potentials of all cathodes due to the absence of glow current in the common load resistor. Of all the cathodes, the favored candidate for first reignition is the cathode whose root is adjacent to the tip at which extinction took place. This is because that region has the greatest density of recently generated gas ions. For this reason the cathode whose root is adjacent to the extinguishing tip will first break down into a glow discharge at its root. This cathode, having thus seized at its root the mutually exclusive discharge, will cause this glow, which is limited by the circuit constants to cover only a fraction of the area of a cathode, to move bodily over the surface of the cathode from its root to its tip. This is because there is a gradient of electrostatic field in the space surrounding the unipotential cathode due to the fact that the root of the cathode is more remote from the common anode than is its tip. The glow, having thus displaced itself to the new tip, is ready for another sequential progression under the action of a subsequent ext1nguis hing pulse. It is to be noted that the basic geometry of counting electrodes capable of pr'o- '2 ducing this phenomenon is disclosed and claimed in the co-pending application.

The present invention teaches a particular structure which is especially suited for reliably using these extinguishing pulses. In addition, I disclose a circuit adapted to utilize this tube to its best advantage. 1

An object of my invention is to provide a stable self-indicating decade counter having a minimum of auxiliary equipment and capable of direct electrical read-out.

Other objects are implicit in the accompanying specifications and claims.

In the drawings:

Figure 1 is a section in plan of the preferred embodiment of my invention;

Figure 2 is the section in elevation through 22 of Figure 1;

Figure 3 is the schematic diagram of a simplified circuit associated with the tube of Figure 1; and

Figure 4 is the schematic diagram of a preferred circuit utilizing the tube of Figure 1.

In Figure 1, a glass tube envelope I contains the common circular anode 2 formed of sheet metal, supported by lead 3 which emerges from the top of the envelope l. The tube is filled with a suitable gas such as neon, hydrogen or argon, under relatively low pressure, say 20 m. m. of mercury. The ten cathodes 4 to It emerge from conventional metal to glass seals to form a circle of connection pins. Each cathode 1 to i3 rises to the median plane of anode 2 at an extreme radius and thence goes radially inward to a knee or root, from which point it passes in a direction approximately tangential to a common circle concentric with and greater in diameter than the anode 2, to intersect a tip member or cross bar M to 23 respectively. These crossbar tip members l4 through 23 are preferably radial to the anode and approach the anode 2 and the respective root or knee of the adjacent cathode with approximately equal gaps. In this way, elements I4 through 23 may be said to be bridge members which intervene in the gap between a root and the anode. The envelope l is provided with a sealed-off pumping tubulation element 24.

In Figure 3, the cathodes 4 through I3 of the tube of Figure 1 are each connected through an individual resistor 25 to a common ring connection 6|. Each resistor 25 is provided with a parallel capacitance 26. Switch 2'17 is provided. to initiate the discharge on cathode 4 as an index electrode; the direct current potential provided by source 28 is applied between the cathode rin'g connection 6! and the anode connection 3 through the common load resistor 32, coupling capacitances 29 and 30 to permit input pulses 3! to be impressed across the common load resistor 32.

In operation, the tube of Figure 1 in the circuit 4, Figure 3, performs as follows: On the opening of normally closed switch 2?, the discharge is set up on the tip across bar [4 of cathode 4. The potential of source 28 together with the values of resistors 25 and 32 are chosen so that the area of glow covering a given cathode is limited to that of the cross bar plus an area of shank approximately equal to one-half of that of the cross bar. Under these circumstances the glow will embrace a volume of gas which is contiguous to the knee of the adjacent cathode, that is, in the case of a glow embracing cross bar l4, the glow will spread throughout the gap bu tween tip I4 and the knee of cathode 5. By vir tue of resistors-25 the potential oncathode-, after closure of switch 21, will be lower than that on the other cathodes due to the drop in the resistor 25 sustained by the glow current unique to cathode 4.

On the impression of a pulse of the polarity shown at input terminals 3 I, the glow on cathode 4 will be driven to extinction. However, since condensers 26 tend to perpetuate the given potentials, the common rise in potential of all cathodes due to the disappearance of glow current through common load resistor 32 will be associated with a lag in the potential of cathode 4 behind the rise of the others. Consequently, the specific one of the remaining cathodes which will recapture the discharge first will depend on the ionic population associated with any given cathode.

Evidently, cathode 5 will be the first to recapture discharge since the cross bar structure of tip l4 has surrounded the root or knee of cathode 5 with ions during its tenancy of the discharge. For this reason, as the potentials of the several remaining cathodes rise equally, the cathode which has been made preferential, namely cathode 5, will capture the discharge at its root. On cessation of the input pulse and coincident with the capture of discharge, the glow area on cathode 5 will progress along the cathode, due to the potential gradient, until it occupies the same area of cross bar and shank characteristic of the previous position of equillibrium. This mechanism of transfer obtains for each of the subsequent positions of cathode equillibrium until the cycle is completed.

Since each registering cathode is provided with a private load resistor 25, it is possible by means familiar to those skilled in the art to transmit or read-out the information implicit in one such register at any time. For cascade operation of such decades, it is possible to use the voltage pulses appearing across the index resistor 25 at terminals 33 as a source of frequency divided pulses to actuate a similar successive decade.

In Figure 4 the alternate cathodes 4, 6, 8, II] and I2 of tube l are each provided with a load resistor 36 which terminates in the common connection 60. Similarly, the remaining alternate cathodes 5, l, 9, H and [3 are provided with individual load resistors 35 terminating in the,

common connection 59. This division of the alternate electrodes into two separately energizable circuits permits a greater difference of potential to be set up between adjacent cathodes than is possible by means of the load resistors 25 of Figure 3, due to the :small glow currents invo e The two triodes 43 and 44 are the two sections of a duo-triode connected in a conventional Eccles- Jordan type of circuit having two states of stable equilibrium according as one or the other of the triodes is conducting. Each input impulse is impressed on the grids-oftriodes 43 and 44 via terminals'M and condensers 42, thereby causing the conduction to shift between the triodes 43 and 44. The remainder of this circuit comprises plate load resistors 49, plate voltage supply 41, grid resistor51.,and the R. C. transfer pairs 55-53 and 5456. The bleeder composed of resistors 55 and maintains the cathodes of triodes 43 and .44 at ..a predetermined potential above ground. -The two triode sections 45 and 46 which are parts of a duo-triode are connected -ascathode followers which serve to couple the since the common bus-'50 is directly connected to the cathode of triode 4 5. Coincident With-the lowered potential of the cathodes-served by bus 60, there will be a rise of the potential of bus-59, since conduction in triode-43 requires nonconduction in triode-44. This in turnpermits *a high positive potential tobe impressed onthe grid of triode 46, thereby producing a large voltage drop inits cathode load resistor 52 and raising the potential of'cathodes 5,1,5, l l and I3." Conversely, conduction-in triode 44Lw-ill cause depression of the potentials of the cathodes served by bus 59 and elevation of the potentials of the cathodes served by bus 60. v V w The crystal or thermionic rectifying diodes 64 form parts of two identical auxiliary circuits designed to cause an overlap of the .potential changes which take place between adjacent cathodes in the tube i. This is accomplished by. causing the time constants of the circuits including condenser 62, high valued resistor 63, and diode 64 to have radically diiferent values depending on the polarity of the pulses appearing on the grids of triodes 45 and 46. Thus these auxiliary circuits will oppose a sudden positive increase of the potential on either grid of triodes 45 or 46, since the diodes do not conduct for this polarity of change and cause.condenserst1 to be fully effective in opposing-change of either of these grid potentials. However, for a sudden decrease of potential of either grid, the corresponding diode 64 will conduct, thus allowing as rapid change in the negative direction as the remaining time constants of the system will permit. The net result of these one-way time constant circuits is to delay the rise of potential glow-discharge due to the consequent mea t:

lowered potentials on adjacent'cathodes. '-Tlil s overlap insures positive transfer of the discharge from the tip crossbar member of one cathode to the knee or root of the correct adjacent cathode.

It has been found that the distributed capacitances of the electrodestogether with the physics of the glow discharge growth and decay may often introduce enough of this overlapping action as to obviate the use of the auxiliary components 62, 63 and 54.

The operation of the system shown in Figure 4 is as follows: To initiate the glow discharge on cathode 4, the normally closed switches 31, 38 and 39 are momentarily opened. This causes triode 43 to conduct, thereby lowering the potential on bus 60 and giving the glow to cathode 4 alone. On receipt of a negative pulse at input terminals 4|, the conduction is reversed between triodes 44 and 43, but due to the effect of overlap-capacitance 62, the potential does not immediately rise on bus (5 so that both cathodes 4 and 5 are momentarily maintained at an approximately equal potential. This situation causes a double glow discharge to occur; one on the cross bar member of cathode 4 and one on the root of cathode 5. There can be no ambiguity as to the position of the glow on cathode 5 at this instant because of the over-abundance of ions from the glow on crossbar I 4 to kindle the breakdown on the root of cathode 5. The delaying action of capacitance 62 will very shortly end, and the potential of bus 60 together with that of cathode 4 will rise and extinguish its glow due to the action of the common load resistor 48 which is ad usted so as to be incapable of normally sustaining more than one cathode glow. An unique glow discharge having been established on the root of cathode 5, this glow will proceed to move along the extended area of the cathode under the electrostatic gradient consequent to the geometry of the tube and will come to equilibrium so as to cover the crossbar member l5 of cathode 5. This motion of the position of glow on the surface of cathode 5, however, has trans ported the region of ion density away from cathode 4 and into intimate contact with cathode 6. Consequently, the next input impulse will inverse repeat the above steps to transfer the discharge to the tip of cathode 6. This process is repeated seriatim to give cyclic register of the tube for continued input impulses. For cascade operation, the pulses appearing across the load resistor 36 of index electrode 4 are available at the output terminals 48.

It will be recognized that there are many different geometric forms of electrodes which may be employed by those skilled in the art to accomplish the principle of glow transfer taught by my invention. The scope of this invention, however, is intended to cover any form of cathode glow surface which has two points or areas between which there exists such a difference of electrostatic field intensity that the glow, having been initiated at the first point, will move to the second point to attain equilibrium.

Also, in the geometry shown, it is to be noted that the gradient of electric field lying along the extended path of the cathodes (which causes the displacement of the glow discharge) is due not only to the gradient of physical separation as one passes from tip to root of a cathode, but also to the fact that the tip presents a much smaller radius of curvature and hence more concentrated field than the smoothly curved knee or root of the cathode.

What I claim is: 1

1. In a gaseous discharge device, the combina tion comprising an anode, a plurality of cathodes each having a tip portion located near said anode and a root portion located more remotely from said anode, and a corresponding plurality of conductive bridge members integral with the tip portions of said cathodes and located in the space between the anode and the root portion of one adjacent cathode.

2. In a gaseous discharge registering device, the combination comprising a gaseous discharge tube, an anode for said discharge tube, a plurality of cathodes for said tube, each having a root area and a tip area, a crossbar member integral with said tip area, and electric field gradient mean including the oblique positioning of said root areas relative to said anode to cause a glow discharge initiated on said root area to move to said tip area.

3. In a gaseous discharge device for registering pulses, the combination comprising an anode, an even number of cathodes positioned along a closed path, each cathode having a root area of unstable glow, said root area. being located more remotely from said anode to provide an electric field gradient and a tip area of stable glow, the root areas of any cathode being adjacent to the tip area of one of its two adjacent cathodes, means responsive to said pulses for depressing the potentials of a given set of the alternate members of said cathodes relative to said anode, and means for subsequently elevating the potentials relative to said anode of the remaining members of said cathodes.

4. In a gaseous discharge device for efiecting storage of electrical manifestations wherein the transfer of a glow discharge from one stable position to another indicates the storage of one electrical manifestation; a single anode, and a plurality of cathodes positioned in sequence along a closed glow transfer path, each of said cathodes having a portion substantially tangential to said anode and a portion substantially perpendicular thereto so that the application of a potential to a cathode creates a potential gradient therealong relative to said anode.

5. In a gaseous discharge storage device of the glow transfer type wherein the preselected transfer of a glow discharge from one area of stable glow discharge to another area of stable glow discharge, via a path of unstable glow discharge, represents the storage of a predetermined value; a plurality of cathodes equal in number to the storage capacity of the device; and an anode common to each of said cathodes, each cathode being formed from a single homogenous material and positioned unequally along its length to said anode so that a preselected portion of each cathode constitutes a path of unstable glow discharge and a different portion of each cathode constitutes an area of stable glow discharge, wherein said portion constituting a path of unstable glow discharge of each cathode is substantially tangential to said anode and said portion constituting an area of stable glow discharge of each cathode is substantially perpendicular to said anode.

6. The gaseous discharge storage device set forth in claim 5 wherein the portion of each cathode constituting said area of stable glow discharge is intermediate the anode and the portion constituting said area of unstable glow discharge of a cathode adjacent thereto so that a depressing of the potential applied to said first mentioned cathode causes the glow discharge to be transferred from the area of stable glow discharge thereof to the portion constituting a path of unstable glow discharge of the second mentioned cathode and automatically progress therealong to the portion of said second mentioned cathode constituting the area of stable glow discharge.

References Cited in the file of this patent UNITED STATES PATENTS Name Date Healy Feb. 21, 1933 Number Number 8 Name Date Rockwood, Jr 1 Dec. 26, 1939 Mumma etal Apr. 9, 1946 Wales, Jr -1 June 15,1948 Lyman, Jr June 14, 1949 Reeves Apr. 25, 1950 Reeves Aug. 1, 1950 Loughren May 15, 1951 Hough May 22, 1951 Townsend Aug. 12, 1952 Von Gugelberg Nov, 18,1952 

